Pharmacology General 7c1c5805 Extended-spectrum beta-lactamases (ESBLs) are characterized by activity against all except : A Penicillinases B Cephalosporinases C Oxyimino–cephalosporinases D Carbapenems High-Yield Explanation Carbapenems like imipenem are the only beta-lactams reliably efficacious against ESBL producing bacteria.